The Hongwu Emperor of the Ming Dynasty in China introduces the census registration system of lijia, or the hundreds-and-tithing system, throughout the Yangzi valley. This system groups households into units of ten and groups of one hundred, whereupon their capacities for paying taxes and providing the state with corvée labor service can be assessed. The system becomes fully operational in 1381, when it counts 59,873,305 people living in China (the historian Timothy Brook asserts that the number was much higher, somewhere between 65 million and 75 million).